| Year | Count |
|---|---|
| 1962 | 10 |
| 1963 | 10 |
| 1964 | 10 |
| 1965 | 25 |
| 1966 | 53 |
| 1967 | 54 |
| 1968 | 113 |
| 1969 | 155 |
| 1970 | 261 |
| 1971 | 350 |
| 1972 | 348 |
| 1973 | 274 |
| 1974 | 378 |
| 1975 | 378 |
| 1976 | 313 |
| 1977 | 380 |
| 1978 | 373 |
| 1979 | 481 |
| 1980 | 476 |
| 1981 | 484 |
| 1982 | 440 |
| 1983 | 462 |
| 1984 | 444 |
| 1985 | 489 |
| 1986 | 407 |
| 1987 | 354 |
| 1988 | 337 |
| 1989 | 339 |
| 1990 | 285 |
| 1991 | 263 |
| 1992 | 244 |
| 1993 | 211 |
| 1994 | 138 |
| 1995 | 96 |
| 1996 | 93 |
| 1997 | 46 |
| 1998 | 34 |
| 1999 | 65 |
| 2000 | 44 |
| 2001 | 32 |
| 2002 | 5 |
| 2004 | 12 |
| 2005 | 12 |
| 2006 | 46 |
| 2007 | 20 |
| 2010 | 10 |